ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Accumulated Other Comprehensive (loss) income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Accumulated other comprehensive (loss) income, net of tax:
Balance	$ 1,169,583	$ 1,192,620
Other comprehensive loss, net of tax	(4,259)	(43,199)
Balance	1,191,253	1,155,287
Accumulated Other Comprehensive (Loss) Income
Accumulated other comprehensive (loss) income, net of tax:
Balance	(94,379)	(6,181)
Other comprehensive (loss) income before reclassifications	(5,330)	(42,695)
Amounts reclassified from accumulated other comprehensive loss	1,071	(504)
Other comprehensive loss, net of tax	(4,259)	(43,199)
Balance	(98,638)	(49,380)
Securities
Accumulated other comprehensive (loss) income, net of tax:
Balance	(100,870)	(7,864)
Other comprehensive (loss) income before reclassifications	(4,313)	(48,075)
Amounts reclassified from accumulated other comprehensive loss	1,551	116
Other comprehensive loss, net of tax	(2,762)	(47,959)
Balance	(103,632)	(55,823)
Defined Benefit Plans
Accumulated other comprehensive (loss) income, net of tax:
Balance	(5,266)	(1,306)
Other comprehensive (loss) income before reclassifications	155	683
Amounts reclassified from accumulated other comprehensive loss	(260)	(641)
Other comprehensive loss, net of tax	(105)	42
Balance	(5,371)	(1,264)
Derivatives
Accumulated other comprehensive (loss) income, net of tax:
Balance	11,757	2,989
Other comprehensive (loss) income before reclassifications	(1,172)	4,697
Amounts reclassified from accumulated other comprehensive loss	(220)	21
Other comprehensive loss, net of tax	(1,392)	4,718
Balance	$ 10,365	$ 7,707